Types of Chemical Reactions 8-2

Beaker Breaker Balance the following equation: ______H 3 PO 4  _______H 4 P 2 O 7 + ______H 2 O

Beaker Breaker Predict the reaction that might occur when aluminum reacts with hydrochloric acid. Write a balanced equation for this reaction.

5 types of chemical reactions: 1.synthesis (composition) 2.decomposition 3.single-replacement (displacement) 4.double-replacement (displacement) 5.combustion

Synthesis Reactions 2 or more substances combine to form a new compound 2 H 2 + O 2  2H 2 O

Decomposition a single cmpd undergoes a rxn that produces 2 or more simpler substances H 2 CO 3  H 2 O + CO 2

Decomposition of… binary cmpds metal carbonates metal hydroxide metal chlorates acid

Single Replacement Reaction one element replaces a similar element in a cmpd 2 Al + Fe 2 O 3  Al 2 O Fe

Single Replacement Reaction of… a metal in a cmpd by another metal hydrogen in water by a metal hydrogen in an acid by a metal replacement of halogens

Double replacement reactions ions of 2 cmpds exchange places in an aqueous solution to form 2 new cmpds ZnBr AgNO 3  Zn(NO 3 ) AgBr

Double displacement reactions….. formation of a precipitate formation of a gas formation of water

Combustion Reactions substance reacts with oxygen and releases a large amount of energy (light and heat) hydrogen + oxygen  water vapor hydrocarbon + oxygen  carbon dioxide + water

Combustion (burning) of propane: C 3 H 8(g) + O 2 

C 3 H 8(g) + 5O 2(g)  3CO 2(g) + 4H 2 O (g)

Practice Complete #2 on page 264

#2 page 264 a.Synthesis b.Single-replacement (single-displacement) c.Decomposition d.Combustion e.Decomposition f.Synthesis g.Double-replacement (double-displacement)

Beaker Breaker Identify the following reactions as either synthesis, decomposition, single replacement, double replacement, or combustion: 2C 2 H 6 + 7O 2  4CO 2 + 6H 2 O Ca + 2HCl  CaCl 2 + H 2

Beaker Breaker Cont. Write a paragraph explaining why the formation of water can be classified as a synthesis or combustion.

In Depth Look at Types of Chemical Reactions

synthesis (composition) decomposition single-replacement (displacement) double-replacement (displacement)

Synthesis Reactions 2 or more substances combine to form a new compound 2 H 2 + O 2  2H 2 O

Reactions of metals with oxygen and sulfur magnesium metal + oxygen  barium + sulfur (S 8 ) 

2Mg (s) + O 2(g)  2 MgO (s 8Ba (s) + S 8(s)  8BaS (s)

Some metals can form oxides of varying oxidation #: iron + oxygen  iron(II) oxide iron + oxygen  iron(III) oxide

Some metals can form oxides of varying oxidation #: iron + oxygen  iron(II) oxide 2Fe (s) + O 2(g)  2FeO (s) iron + oxygen  iron(III) oxide 4Fe (s) + 3O 2(g)  2Fe 2 O 3(s)

Nonmetals can also form oxides S 8(s) + 8O 2(g)  8SO 2(g) C (s) + O 2(g)  CO 2(g) 2C (s) + O 2(g)  2CO (g)

Reactions of metals with halogens potassium + iodine  strontium + bromine  cobalt + fluorine  [cobalt(III) ion forms]

Reactions of metals with halogens potassium + iodine  2K (s) + I 2(g)  2KI (s) strontium + bromine  Sr (s) + Br 2(l)  SrBr 2(s) cobalt + fluorine  [cobalt(III) ion forms] 2Co (s) + 3F 2(g)  2CoF 3(s)

Synthesis reactions with metal oxides active metals* oxides + water  hydroxides calcium oxide + water  *(see p. 266)

CaO (s) + H 2 O (l)  Ca(OH) 2(s)

Synthesis reactions with nonmetal oxides nonmetal oxides + water  oxyacids sulfur dioxide + water 

SO 2(g) + H 2 O (l)  H 2 SO 3 when SO 2 reacts with rain water to form H 2 SO 3, it can further react with the atmosphere…. H 2 SO 3 + O 2  2 H 2 SO 4

Synthesis reaction of metal oxide & nonmetal oxide calcium oxide + sulfur dioxide 

CaO (s) + SO 2(g)  CaSO 3(s)

Beaker Breaker Identify the following reactions as either synthesis, decomposition, single replacement, double replacement, or combustion: K + Cl 2  KCl CH 4 + O 2  CO 2 + H 2 O Fe + HCl  FeCl 3 + H 2

Decomposition a single cmpd undergoes a rxn that produces 2 or more simpler substances H 2 CO 3  H 2 O + CO 2

Decomposition of… binary cmpds metal carbonates metal hydroxide metal chlorates acid

Decomposition of binary cmpds simplest decomposition rxn decomposition into elements ELECTROLYSIS: decomp by an electric current 2 H 2 O (l) electricity --->

2 H 2 O (l) electricity ---> 2H 2(g) + O 2(g)

Decomposition of Metal Carbonates when heated (∆), produce a metal oxide and carbon dioxide gas CaCO 3(s) - ∆ 

CaCO 3(s) - ∆  CaO (s) + CO 2(g)

Decomposition of Metal Hydroxides all metals except Gp 1 decomp when heated to produce metal oxides and water Ca(OH) 2(s) - ∆  CaO (s) + H 2 O (g)

Decomposition of Metal Chlorates when heated, decompose to produce a metal chloride and oxygen 2KClO 3(s) - ∆  2KCl (s) + 3O 2(g)

Decomposition of Acids Many acids decompose into nonmetal oxides and water H 2 SO 4(aq) - ∆  H 2 CO 3(aq) 

H 2 SO 4(aq) - ∆  SO 3(g) + H 2 O (l) H 2 CO 3(aq)  CO 2(g) + H 2 O (l)

Single Replacement Reaction one element replaces a similar element in a cmpd 2 Al + Fe 2 O 3  Al 2 O Fe

Single Replacement Reaction of… a metal in a cmpd by another metal hydrogen in water by a metal hydrogen in an acid by a metal replacement of halogens

Replacement of a metal in a cmpd by another metal aluminum + lead(II) nitrate  (p. 266 Al is more reactive than Pb so a spontaneous reaction will occur)

2Al (s) + 3 Pb(NO 3 ) 2(aq)  3 Pb (s) + 2Al(NO 3 ) 3(aq)

Replacement of H in water by a metal (active) very active metals (i.e. Gp 1) pulls one H from the water sodium + water 

2Na (s) + 2H 2 O (l)  2NaOH (aq) + H 2(g)

Replacement of H in water by a metal (less-active) less- active metals reacts with steam and pulls-off both hydrogens from the water iron + water 

3Fe (s) + 4H 2 O (g)  Fe 3 O 4(s) + 4H 2(g)

Replacement of H in an acid by a metal more-active metals reacts with some acidic soln’s magnesium + hydrochloric acid 

Mg (s) + 2 HCl (aq)  H 2(g) + MgCl 2(aq)

Replacement of Halogens a more reactive halogen will replace a less-active halogen the higher up in the Gp 17 family, the MORE reactive the halogen Reactivity: F>Cl>Br>I chlorine gas + potassium bromide sol’n 

Cl 2(g) + 2KBr (aq)  2KCl (aq) + Br 2(l)

fluorine gas + sodium chloride sol’n  bromine liquid + potassium chloride sol’n 

fluorine gas + sodium chloride sol’n  F 2(g) + 2NaCl (aq)  2NaF (aq) + Cl 2(g) bromine liquid + potassium chloride sol’n  Br 2(l) + KCl (aq)  no reaction (NR)

Double replacement reactions ions of 2 cmpds exchange places in an aqueous solution to form 2 new cmpds ZnBr AgNO 3  Zn(NO 3 ) AgBr

Double displacement reactions….. formation of a precipitate formation of a gas formation of water

Formation of a precipitate one product is insoluble (or just slightly soluble) …see page 427 potassium iodide + lead (II) nitrate 

2KI (aq) + Pb(NO 3 ) 2(aq)  PbI 2(s) + 2KNO 3(aq)

Formation of a gas one product is an insoluble gas and bubbles out iron(II) sulfide + hydrochloric acid sol’n 

FeS (s) + 2HCl (aq)  H 2 S (g) + FeCl 2(aq)

Beaker Breaker Complete and balance each of the following reactions, and then identify each by type. 1.Calcium + sodium nitrate  ________ 2.Silver nitrate + potassium iodide  _____

Formation of Water one of the products yields the molecular cmpd water hydrochloric acid + sodium hydroxide 

HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O (l)